I'm needing any info on a Cologne 2.9 Litre v6 EFI from a 1988 Bronco II 4x4 for a
project I'm working on.
What are it's stock stats?
Any rebuild recommendations?
Maximum upgrade performance mods?
Etc.
From the Wikipedia..
The North American version of this engine suffered from several serious reliability issues over its lifespan.
Cylinder head cracking was very common in early models, but affected all model years. Compared to the relatively stout European heads, the North American 2.9 had apparently been subject to a reduction of material around the valve stem guides and rocker shaft mounting pedestals. Some engines would suffer from this failure after overheating only once, while some would fail without overheating at all.
The cylinder heads underwent a redesign for the 1989 model year, receiving additional material in some problem areas. This helped to reduce the chances of this specific failure, but it was still an issue. Some of these head castings are supposedly printed with the "89TM" designation, but there has been no verification of these claims as the "86TM" designation is usually found on the 1989 and newer heads as well. The redesigned heads also have larger diameter bosses for accessory mounting than the 1st design heads.
After-market heads are also available from World Products, with better design improvements to the early OEM design. These heads use the early model narrow bosses for accessory mounting, so fitment of 1989 and newer accessory brackets will require modification.
Additionally, oiling problems were common, and added to the poor reputation of the North American 2.9. Although these problems mainly affected poorly maintained or high mileage engines, it occasionally affected low-mileage engines with proper maintenance as well. The symptom of these problems is serious valve train noise. This is due to a number of design faults. Valve train oil pressure was entirely dependent upon a supply fed through the two center cam bearings. Even slight bearing wear could cause complete loss of oil pressure to the hydraulic valve lifters, rocker shaft, and rockers. Excessive internal "bleeding" through the half-moon camshaft thrust plate also contributed to this, though this can possibly be remedied by reinstalling the thrust plate in an upside-down position.
In the event that a cylinder head crack occurs, coolant can often enter the crankcase, contaminating the oil. This quickly leads to cam bearing damage, triggering valve train oil pressure loss. As a result, these two design faults have led to catastrophic engine failure in many North American 2.9s.
Regardless of these problems, many of these engines are still on the road in the US, and when maintained properly, can be highly reliable powerplants. Regular oil changes and stringent cooling system maintenance is essential if owners of early-model 2.9s wish to avoid trouble